上海城郊不同农业用地类型土壤硝化和反硝化作用

采用气压过程分离(BaPS)技术对上海城郊不同农业用地类型土壤总硝化速率和反硝化速率进行了测定.结果表明:不同农业用地类型土壤总硝化速率和反硝化速率差异显著(p<0.05).其中大棚蔬菜总硝化速率和反硝化速率最高;在土壤含水量15%～30%范围内.土壤总硝化作用和反硝化作用对氮损失的贡献率分别为46.8%,53.2%.土壤含水量和土壤通气孔隙度的适度增加均有利于土壤硝化作用和反硝化作用的进行;总硝化速率与土壤含水量、土壤通气孔隙度、全氮含量呈显著性相关(p<0.05),与土壤N_3~--N呈极显著性相关(p<0.01);反硝化速率与土壤含水量、N_3~--N、全氮呈显著性相关(p<0.05),与土壤通气孔隙度呈极显著性相关(p<0.01);中等土壤含水量范围内,影响土壤硝化作用、反硝化作用的环境因子趋于多样和复杂化,各种土壤环境因子共同影响和决定土壤硝化和反硝化过程.

Nitrification and Denitrification with Different Agricultural Land Use Patterns in the Suburb of Shanghai

A BaPS(Barometric Process Separation)system was introduced to determine soil gross nitrification rate and denitrification rate among different agricultural land use patterns in Shanghai suburban areas.The result indicated that different patterns of agricultural land use had significant effect on gross nitrification and denitrification rate(One-way ANOVA,p<0.05),the gross nitrification rate of greenhouse vegetables fields was highest.With soil water content varied between 15%and 30%,the proportion of nitrification and denitrification that respectively contributed to soil nitrogen loss was 46.8%and 53.2 9/6 respectively.Improvement of soil moisture status and soil aeration moderately would promote soil nitrification and denitrification process.Gross nitrification rate were positively related to soil content water,soil aeration porosity,total nitrogen content(p<0.05),and soil NO_3~--N showed a significant correlation(p<0.01).Denitrification rate and soil moisture,NO_3~--N,total nitrogen were related(p<0.05),and soil aeration porosity was significantly associated(p<0.01).In the middle range of soil moisture,affecting soil nitrification,denitrification of the environmental factors become more diverse and complex,and a variety of soil and environmental factors iointly affect and decide soil nitrification and denitrification process.